Forest nurseries play a vital role in production of quality seedlings of forest species for large scale plantation programmes. Apart from this, every forest nursery is acting as a resource center where many ideas/learnings are acquired by nurserymen and researchers. Several kinds of plant abnormalities such as double seeds in Mammea suriga, polyembryony in Vateria indica, twin seedlings and triplet seedlings in Garcinia indica and albinism in Dysoxylum malabaricum and Caesalpinia bonduc (Gunaga et al 2006b, Gunaga and Vasudeva 2008, Gunaga et al 2008, Gunaga and Vasudeva 2011, Gunaga et al 2018) have been documented from the forest nurseries in different forest species.

In the present study, albino seedlings in soapnut (Sapindus trifoliatus L), one of the commercial NTFPs of the country, have been reported. Among several species of Sapindus in India, only four species viz S mukorossi, S trifoliatus, S laurifolius and S emarginatus are distributed in the natural forests (Singh and Sharma 2019) and all these species are popularly known as soapnut. These trees are grown in various landuse systems like home gardens, avenue/roadside plantations and gardens. Pericarp (pulp/rind) of this fruit is harvested and used as soap/detergent to clean the hair, ornamentals, silk cloths, wools etc (Umraosingh et al 1996, Singh and Sharma 2019). Pericarp contains 10 to 18 per cent saponin; therefore there is substantial demand of it for industrial usages such as herbal, soap, pharmaceutical and photofilm industries (Naidu et al 2000).

The study was carried out to find out the effect of different pre-sowing treatments on seed germination and their attributes in soapnut. A seed lot of healthy fruits was collected from a single tree located at the campus of Navsari Agricultural University, Navsari, Gujarat. Seeds were separated by removing pericarp and exposed to twelve different pre-sowing treatments including control (Table 1) and each treatment consisted of three replications with 75 seeds per replication (Lakum 2022). Germination count and seedling abnormality were recorded.

The seed germination started within six to nine days with an overall mean of seven days among the twelve treatments and seed germination varied from 24 to 70 per cent at 21 days after sowing. However the control treatment achieved 57 per cent germination (Lakum 2022). During germination, a substantial number of albino seedlings was recorded in different pre-sowing treatments and the number of such abnormal plants is reported in Table 1. All the seeds used in the study were collected from a single tree and the total number of albino seedlings recorded was 382 representing about 23 per cent of the total seedling stock raised in the experiment (Plate 1). The survival of the plants was regularly monitored, however, all those seedlings survived up to 17 to 25 days; thereafter, none of the albino seedlings survived. Considering individual treatment, albino seedlings ranged from 12.88 (T₃) to 32.54 per cent (T₄). Seeds exposed to T₂ resulted in 63 per cent germination and all of them were normal green plants and no single albino seedling was noticed in this treatment. Here pre-sowing treatments may not be a factor for development of albinism. In fact it could be a kind of genetic disorder.

Albinism, a rare occurrence in plants, is caused by lack of chlorophyll pigment and they are short-lived. Since such albino plants do not manufacture their own food, hence their survival was only for few days that may have depended upon the storage of food in the cotyledon. Such kind of observation for the first time was noticed in Sapindus trifoliatus by Gunaga et al (2006a) with the report of a single albino seedling out of 800 plants raised in the forest nursery of College of Forestry, Sirsi, Karnataka. Similarly, Anandalakshmi et al (2013) reported albinism in S emarginatus from Tamil Nadu. Out of four populations studied viz Thengumarada, Pillur, Mettupalayam and Palani, only the Pillur source showed albinism, whereas, seedlings raised using two CPTs from Pillur expressed the albinism and these albino seedlings showed stunted growth than normal seedlings.

As compared to these reports, in the present study highest albinism of 23 per cent in S trifoliatus was recorded. Gunaga and Vasudeva (2011) documented albino seedlings in different forest species where possible reasons for albinism could be mutation, natural selfing, reduced population sizes and inbreeding within the population (Indira and Koshy 1986, Gunaga and Vasudeva 2011). Reporting such information may be useful in ecology and population genetic studies.

Figures in parentheses are arc sine transformed values

References